Most of the strains have been isolated by staff and students from either NIVA, UiO or UoC, and most originate from lakes and rivers or coastal or open oceanic waters in Northern Europe. The strains span a wide taxonomic diversity and belong to 10 different phyla, and many are unique for this collection. The collection also contains strains from all over the world obtained from research projects at the three institutions or from exchange with other collections. Researchers from Norway and abroad have also deposited cultures at NORCCA as a resource for further exploitations. About half of the strains are from freshwater or terrestrial habitats and half from marine or brackish waters. About 100 strains are macroalgae and the remaining are microalgae and cyanobacteria.
The marine cultures are grown in various seawater medium (TL, K, L1, Z8) at salinities ranging from 10-40 PSU (most at 25 and 30 PSU) and temperatures from 4-20 °C. The stock cultures are grown in temperature-controlled rooms. At UiO the stock cultures are divided into six different rooms with temperatures 4, 6,12,13,16,19 °C to meet the demands of the various strains. At NIVA the strains are kept at 18 and 15 °C. The strains are transferred into new medium every 2-6 weeks depending on growth rate. The cultures are grown in autoclaved glass tubes or flasks.